I would guess that a digestive system that can extract adequate nutrition from grass will extract something of value from meat. On the other hand, if the meat c

I would guess that a digestive system that can extract adequate nutrition from grass will extract something of value from meat. On the other hand, if the meat content became a significant part of the diet, I can imagine it could become harmful, for example by messing with the digestive process or by delivering toxic levels of certain products.